Magneto-optic memory element

Abstract

A magneto-optic memory element includes a GdTbFe recording layer sandwiched between a pair of transparent AlN dielectric layers. At least one of the pair of transparent AlN dielectric layers is extended to have a size larger than the GdTbFe recording layer so as to cover the peripheral edge of the GdTbFe recording layer, thereby protecting the GdTbFe recording layer from oxygen and moisture. An Al-Ni alloy reflection film is formed on one of the pair of transparent AlN dielectric layers in order to increase the apparent Kerr rotation angle produced by the magneto-optic memory element.

What is claimed is: 
     
       1. A magneto-optic memory element comprising: a transparent substrate;   a first transparent oxygen-proof, moisture-proof dielectric layer formed on said transparent substrate;   an alloy thin-film magneto-optic recording layer formed on said transparent oxygen-proof, moisture-proof dielectric layer;   a second transparent oxygen-proof, moisture-proof dielectric layer formed on said alloy thin-film magneto-optic recording layer;   a reflection layer formed on said second transparent oxygen-proof, moisture-proof dielectric layer; and   said reflection layer including an extended portion making said reflection layer larger than said magneto-optic recording layer, said extended portion being disposed over the peripheral edge of said magneto-optic recording layer so as to protect said peripheral edge from oxidation and moisture.   
     
     
       2. The magneto-optic memory element of claim 1, wherein said reflection layer is an aluminum (Al) reflection layer including an element which prevents the formation of turbidity in the aluminum (Al) reflection layer. 
     
     
       3. The magneto-optic memory element of claim 1, wherein said reflection layer is an Al-Ni alloy film. 
     
     
       4. The magneto-optic memory element of claim 3, wherein said Al-Ni alloy film is formed by a sputtering method with a target of aluminum (Al) to which nickel (Ni) is added. 
     
     
       5. A magneto-optic memory element comprising; a transparent substrate;   a first transparent oxygen-proof, moisture-proof dielectric layer formed on said transparent substrate;   an alloy thin-film magneto-optic recording layer formed on said transparent oxygen-proof, moisture-proof dielectric layer;   a second transparent oxygen-proof, moisture-proof dielectric layer formed on said alloy thin-film magneto-optic recording layer;   a reflection layer formed on said second transparent oxygen-proof, moisture-proof dielectric layer; and   said transparent substrate having a cutaway portion at a periphery thereof, portions of said first dielectric layer, said magneto-optic recording layer, said second dielectric layer, and a portion of said reflection layer at said periphery being displaced by the depth of said cutaway portion, the displaced portion of said reflection layer covering the peripheral edge of the non-displaced magneto-optic recording layer so as to protect said periphera ledge from oxidation and moisture.   
     
     
       6. The magneto-optic memory element of claim 5 wherein said reflection layer is an aluminum (Al) reflection layer including an element which prevents the formation of turbidity in the aluminum (Al) reflection layer. 
     
     
       7. The magneto-optic memory element of claim 5 wherein said reflection layer is an Al-Ni alloy film. 
     
     
       8. The magneto-optic memory element of claim 7, wherein said Al-Ni alloy film is formed by a sputtering method with a target of aluminum (Al) to which nickel (Ni) is added.